1. Field of Invention
This invention relates to novel pyranoindole and thiopyranoindole derivatives, to processes for their preparation and to intermediates used in these processes.
More specifically, the present invention relates to novel pyranoindole and thiopyranoindole derivatives possessing valuable pharmacologic properties. For example, these derivatives exhibit useful antidepressant properties at dosages which do not elicit undesirable side effects. Furthermore the present derivatives exhibit properties useful for the treatment and prevention of ulcers. The combination of these pharmacologic properties together with a low order of toxicity render the pyranoindoles and thiopyranoindoles of the invention therapeutically useful.
2. Description of the Prior Art
Only a rather limited number of reports dealing with pyrano[3,4-b]indole derivatives are available. In the few that do exist, pyranoindoles are treated more in the manner of chemical curiosities. For the most part these reports discuss the preparation of pyranoindoles in which the pyran portion thereof exists as a lactone. For example, see H. Plieninger, Chem. Ber., 83, 271 (1950) and S. Sakurai and T. Ito, Nippon Kagaku Zasshi, 78, 1665 (1957); [Chem. Abstr., 54, 1488f (1960)].
The thiopyranoindoles of the prior art, for example, 5-(3-aminopropyl)-1,3,4,5-tetrahydrothiopyrano[4,3-b]indole, M. E. Freed, et al., J. Med. Chem., 7, 628 (1964) are distinguished from the present compounds of this invention by having a different ring structure and by lacking substituents on the thiopyran ring.